The present invention relates to the use of free-radical generating aromatic diols for preparing polycarbonates having thermal labile free-radical generating groups in the backbone. More particularly, the present invention relates to the employment of free-radical polymerizable organic monomers, such as styrene in combination with polycarbonates having thermally labile free-radical generating groups to produce polycarbonate block copolymers upon thermolysis.
Prior to the present invention, as shown by Crivello, U.S. Pat. Nos. 4,584,356 and 4,677,169, silicone-organic block copolymers were provided by heating a mixture of a silicone prepolymer having chemically combined pinacolate groups and a free-radical polymerizable organic monomer, such as styrene, to produce silicone-organic block copolymers.
As discussed in copending application Ser. No. 07/404,287, polycarbonate block copolymers can be made by the reaction of a peroxide terminated polycarbonate with an ethylenically unsaturated compound, such as styrene, to produce the corresponding polycarbonate-polystyrene block copolymer. The resulting copolymers have been found capable of compatabilizing blends of a polycarbonate with another organic polymer.